#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <cmath>
#include <iomanip>
#include <complex>
#include <queue>
#include <cassert>
#include <stack>
#include <random>
#include <chrono>
#include <map>
#define forn(i, n) for (int i = 0; i < n; ++i)
#define all(a) begin(a), end(a)
#define int long long
#define sqr(x) ((x) * (x))

#ifndef _debug
    #define debug(...) 42
    #define debr(...) 42
#else
    #define debug(x) cout << #x << " = " << x << endl
    #define debr(...) { cout << #__VA_ARGS__ << " = ";  _debr(__VA_ARGS__); }
#endif

using namespace std;

template<class Iter>
void _debr(Iter l, Iter r) {
    cout << "[";
    for (auto it = l; it != r; ++it) {
        if (it != l) {
            cout << ", ";
        }
        cout << *it;
    }
    cout << "]" << endl;
}

template<class C, class F>
ostream& operator<<(ostream &out, pair<C, F> p) {
    return out << "(" << p.first << ", " << p.second << ")";
}

using ll = long long;

mt19937_64 rnd(std::chrono::system_clock::now().time_since_epoch().count());

void solve() {
    int n;
    cin >> n;
    vector<int> a(n);
    forn(i, n) cin >> a[i], --a[i];

    auto make = [&] (int i) {
        assert(a[i] != i);
        assert(a[i + 1] != i + 1);
        swap(a[i], a[i + 1]);
        cout << i + 1 << " " << i + 2 << "\n";
        cout << endl;
    };

    for (int i = 0; i < n; ) {
        if (a[i] == i) {
            ++i;
            continue;
        }

        int j = i;
        while (j < n && a[j] != j) ++j;

        for (int k = j - 1; k >= i; --k) {
            int ps = -1;
            for (int c = k; c >= i; --c) {
                if (a[c] == k) ps = c;
            }
            debr(all(a));
            debug(ps);
            if (ps == -1) {
                cout << "impossible\n";
                return;
            }
            while (ps < k) {
                if (ps + 1 < k && a[ps + 1] == ps) {
                    int r = ps + 1;
                    while (r <= k && a[r] == r - 1) ++r;
                    debug(r);
                    if (r != k + 1) {
                        while (r > ps + 1) {
                            make(r - 1);
                            --r;
                        }
                    }
                }
                make(ps);
                debr(all(a));
                ++ps;
            }
        }

        i = j + 1;
    }

    // forn(i, n) {
    //     cout << a[i] << " ";
    // }
    // cout << "\n";
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    solve();
    return 0;
}